Paper-pressing attachment for recording instruments.



No. 813,005. PATENTED FEB. 20, 1906.

0. HULT.

PAPER PRESS-ING ATTACHMENT POR RECORDING INSTRUMENTS.

' APPLICATION FILED DB0.31,1903.

` or stylus re uires to be adjusted with y 'UNITED STATES PATENT OFFICE.

CHARLES HULT, oF MINNEAPoLIs,M1NNEsoTA. PAPER-PREssl'Ne ATTACHMENT FoR RECORDING INSTRUMENTS.

- Specification of Letters Patent.

Patented Feb. 20, 1906.

Application filed December 31, 1903. Serial No. 187,288.

To alt whom it may concern:

Be it known that I, CHARLES .HULT, a citizen of the United States, residing at Minneapolis, in the county of Hennepin and State o Minnesota, (whose post-office address is 508 Sixteenth avenue southeast, Minneapolis,) have invented certain new and useful Improvements in Paper-Pressing Attachments' My -improved attachment is especially adapted for ap lication to recording instruments of the c aracter enerall known to the trade as the Bristo recor ers, which general term includes volt-meters, registerlng thermometers, ammeters, steam pressure recorders, &c. 1

Instruments of the above character employ a disk or chart which is caused to rotate by clockwork at a predetermined speed. A graduated chart formed of thin paper is secured to and carried by this rotating dial or disk. The recording-mark on the paper record-disk is made by a pen which is automatically moved according to the v ing pressure or to the voltage or flow of t e electric current or to the variation in temperature, according to the character of the instrument;

In practice I have found that it is'practically lmpossible to cause the paper chart `to lie perfectly lat at all points against the rotary disk which carries it, and hence that bulges will occur at various oints on its face. These bulges or uneven su aces of the chart acting on the pen or stylus Awill cause it to lag back, so as to produce a line which does not properly re resent the record which should j e recorde In other words, the accuracy of the instrument is destro ed or impaired by all unevennesses or irregu arities in the surface of the chart.

It will ofcourse be understood that in instruments ofthis character the recording pen eat nicety and t at its action 1s a very de leate one, which is easily interfered with.

I remove the above defect in the action of the recording-pen by the provision of an eX- tremely simple device in the nature of a detachable supporting-bar having a plurality 'of light spring-'fingers that engage the paper recording-disk very close to the lne of travel thereover of the' recordin -pen, and thus keep that ortion of the sai paper recordingdisk whic is acted upon by the pen pressed closely against the rotating supporting-disk which carries it. In 'this way the surface of the paper recordin -disk at the point or place where 1t is engage by the pen is always ke t the constant redetermined relation to t e pen, so that t e pen will produce thereon a recording-line of constant lntensity.

The invention is illustrated in the accomanying drawings, wherein like characters mdicate 'like parts throughout the i several views.-

Figure 1 is a view in front elevation, showing a recording instrument which may be assumed to be a volt-meter havingapplied thereto one \of my im roved disk ressing devlces, some parts of t e case of sai lnstru- Ament being removed.- Fi 2 is a detail in horizontal section on the llne x2 :ci of Fig. 1, some parts being broken away.` Fig. 3 is a detail in section on the line :c3 :c3 o? Fig. 2,

some parts bein broken away and some being removed. i 4 is a detail insection aproximatel on t e line of Fig. 1, and 5 is a etail in section on the line x5 x5 of 1 1.

he numeral 1 indicates the case of the indicator or recorder, which case is provided, as is usual, withfa hin ed annular frame 2, that carries a crystal or isk-like glass pane 3.

The numeral 4 indicates the automaticallyactuating rotary spindle of the instrument, which spindle is located at the axis of the case 1 and carries a metallic disk 5, which is secured thereto in the usual way by a knurled thumb-nut 6, working on the screw-threaded end of said stem 4. v

The numeral 7 indicates the graduated paper record-chart, which is detachably held on the face of the carrying-disk 5 by a'plurality of spring-lips 8, carried by the peripheral ortion of said disk 5.

Tllie automatically-actuated -marking-arm k9 carries at its free end the usual 'pen 10,

which marks upon the face of the chart 7.

My vimproved attachment is afforded by a light metallic bar 11, which at its intermediate portion carries a plurality of sprin presser-fingers 12 and at one end is forme roo IIO,

with a hub 13, that is adapted to telescope loosely over the knurled nut 6 of the stem 4. The free end of the bar 11 is adapted to be engaged underanotched retaining-lu 14 on the side of the case 1, and to secure t e hub end of said arm in Working position it is provided with an approximately U-shaped spring 15, one end of which is secured to said bar and the free end of which works in a slot 16 of said hub 13 and projects beyond the same so that it may be enga ed by the finger. For coperation with the ee end of the sprin the nut 6 is Aformed with a eriphera groove 17, which receives the said iii the spring to detachably hold the bar 11 in working position.

The several spring-fingers 12, it will be noted. by reference particularly to Fig. 1,

., press upon the paper recording-chart 7 at points that lie in the same curved line close to the line of movement of the pen 10, as already more fully stated.

The attachment above described is of very small cost, may be applied in workin position very quickly, and may be quiclgily removed from position, and, furthermore, is lelicient for the purposes had in view.

- It willof course be understood that the ee end ofldevice described is capable of mddification What I claim, and desire to secure by Letters Patent of the United States, is as follows:

In an instrument of the character described, the case 1 having the retaining-lug 14, the rotatin stem 4 screw-threaded at its outer end and, aving a nut 6 with groove 17, the record-carrying disk 5 clamped to said stem 4, by said nut 6, and the automaticallyvibrated arm 9 having the pen or stylus 10, in combination with the detachable bar 11 interlocking at its free end with said lu 14 and provided at its inner end with the hu 13 and spring 15, said hub fitting over said nut 6 and said s ring engaging with said groove 17 thereo and the p urality of spring-fingers 12 on said bar 11, for pressin a paper recording-chart against the sai rotary carryingdisk, substantially as described.

In testimony whereof I affix my signature in presence of two Witnesses.

4 CHARLES HULT. Witnesses:

ELIZABETH H. KELIHER, F. D. MERCHANT. 

